Anti-Müllerian Hormone (AMH) is produced by the granulosa cells within the ovarian follicles. This hormone serves as a measurable marker that helps clinicians assess a woman’s ovarian reserve, which is the remaining supply of eggs. Testing for AMH provides a snapshot of this reserve, but interpreting the result requires considering a woman’s age and clinical history, as the level changes naturally over time.
Understanding AMH’s Role in Fertility
AMH is secreted by the small, developing follicles (pre-antral and small antral follicles) that have not yet been selected for the current menstrual cycle. These follicles are continuously recruited from the dormant pool of eggs within the ovary. The concentration of AMH in the bloodstream is directly proportional to the number of these small, growing follicles.
Measuring AMH levels estimates the size of the overall ovarian reserve. A higher AMH level suggests a larger pool of remaining follicles and a greater egg supply. Conversely, a lower AMH level signifies a smaller reserve. This mechanism makes AMH useful for predicting how ovaries might respond to stimulation during treatments like in vitro fertilization (IVF).
Interpreting AMH Levels by Age
The concept of a “good” AMH level depends entirely on a woman’s chronological age, as the supply of follicles naturally declines over time. For women aged 20 to 24, an optimal AMH range often falls between 3.0 and 5.0 ng/mL. This robust level reflects an abundant ovarian reserve at the peak of reproductive potential.
As a woman moves into her late 20s and early 30s, the benchmark adjusts downward, with 2.0 to 4.0 ng/mL common for those aged 30 to 34. For example, 1.5 ng/mL would be considered low for a 25-year-old, indicating a diminished reserve for that age group. However, for a woman approaching 40, this same 1.5 ng/mL level might be viewed as satisfactory or even better than average.
By the time a woman is 40 to 44 years old, the typical range has narrowed, with levels between 0.5 and 1.5 ng/mL reflecting a normal, age-appropriate reserve. Levels below 1.0 ng/mL are generally classified as low and suggest a diminished ovarian reserve, particularly for women under 35. These age-specific benchmarks underscore that AMH is a relative measure compared to other women in the same age cohort.
Limitations and Context of AMH Testing
While AMH reliably indicates ovarian reserve quantity, it does not provide information about the quality of the remaining eggs. A young woman with a low AMH level may still have a high probability of successful conception due to the age-related quality of her eggs. Conversely, an older woman with a high AMH may face challenges despite having a large reserve.
External factors and certain medical conditions can temporarily skew the AMH result. Women with Polycystic Ovary Syndrome (PCOS) often show elevated AMH levels because of the large number of small follicles characteristic of the condition. Conversely, hormonal contraceptives can suppress AMH levels, leading to a result lower than the woman’s true reserve.
For a complete picture of reproductive health, AMH should always be evaluated alongside other fertility markers by a specialist. These complementary tests typically include a transvaginal ultrasound for Antral Follicle Count (AFC) and blood tests for Follicle-Stimulating Hormone (FSH). AMH is primarily used to predict ovarian response to stimulation in fertility treatments, but it is not a standalone predictor of natural conception.